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R. W. EARLEY March 17, 1964 MUFFLER Original Filed Oct. 3l, 1958 I Eva/Donn roR CONDE/vsn? INVENTOR ROB FIGA.

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United States Patent 3,125,182 MUFFLER Robert W. Earley, Worthington, Ohio, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a

corporation of Pennsylvania Continuation of application Ser. No. 771,069, Oct. 31, 1958. This application Dec. 22, 1961, Ser. No. 162,319

2 Claims. (Cl. 181-53) This invention relates to mufllers, and more particularly to an improved mufer for refrigerant compressors. It is a continuation of application Serial No. 771,069, filed October 31, 1958, now abandoned.

Refrigerating machines of the type having a motorcompressor unit are usually provided with a muffler connected to the compressor discharge line. It is desirable for a discharge muffler to be large in volume and/or provide a long flow path in order that disturbing low frequency sounds, as well as sounds of intermediate and high frequency, will be effectively deadened. In the interest of producing a compact refrigerating machine, it is also desirable that the overall size of the discharge muffler be as small as possible for the noise reduction it accomplishes.

Where it is desired to extend the frequency range of a single chamber muffler to include still lower frequencies, Without altering the muffler shell, the existing mufer shell can be interiorly partitioned to provide a plurality of compartments. These compartments are then connected together by a tube which effectively extends the flow path through the muffler. This practice is disadvantageous from a cost standpoint, however, because the additional parts and labor required appreciably add to the overall manufacturing cost of the muffler.

In accordance with the present invention an improved muffler is provided which is capable of simple and economical manufacture, and which has a lower cut-off frequency than prior art mufflers of comparable size and cost. The improved muffler comprises a hollow shell having an inlet and an outlet for connection in the compressor discharge line. Disposed within the mufiler shell between the inlet and the outlet, is a wall that partitions the shell interior into two compartments. The wall is constructed of two juxtaposed plates, at least one of which has a recess or depression embossed therein to provide a tubular passage between the plates. Preferably, the wall comprises twin plates of flat metal; and it is also desirable that each plate have a similar depression formed therein so that, when like broad surfaces of the two plates are held together, the respective depressions are in complementary relationship. Each plate also has an opening formed therein at or adjacent one end of the depression so that, in properly assembled relationship, the plate openings are offset from each other and provide a flow path between the respective compartments and the tubular passage between the plates.

The component parts of this improved muffler are preferably secured together by a furnace brazing process, an efficient assembly operation commonly used in the construction of refrigeration apparatus. Moreover, fewer dissimilar parts are required to construct this muffler than prior art mufflers; all of which accomplishes savings in manufacturing expense.

The various objects, features and advantages of the invention will appear more fully from the detailed description and claims taken in connection with the accompanying drawings, forming a part of this application, in which:

FIG. 1 is a view, partly in vertical section and partly in elevation, of a motor-compressor unit which embodies the invention and is shown with other, schematically illustrated, parts of a refrigeration system;

FIG. 2 is an enlarged front perspective view of the improved muffler, constructed and arranged according to the invention, with portions of the muffler shell broken away to show the partition employed therein;

FIG. 3 is an enlarged rear perspective view, similar to FIG. 2, of the same muffler;

FIG. 4 is an enlarged front elevational view of the muffler partition of FIG. 2; and

FIG. 5 is a horizontal sectional view of the partition, taken along l-ine V-V of FIG. 4.

The invention, as shown, is applied to a motor-compressor unit which is designated as a whole by the numeral 8 and entirely enclosed within a hermetically sealed casing 9. The motor-compressor unit S includes a piston 10 which slides back and forth in a cylinder 11 when it receives reciprocating forces, through a connecting rod 12 and crank 13, from a vertical shaft motor 14. It will Suice to say that compressed refrigerant gas leaves the compressor cylinder 11 through an outlet 15, passes through muffler 16, and is delivered to a condenser 17 exteriorly of the hermetically-sealed casing 9 by means of a discharge conduit 18. Condensed refrigerant is expanded through expansion means 20 and boiled off in an evaporator 21, from whence it is returned to the motorcompressor unit 8 through a suction line 22. Upon entering the casing 9, refrigerant is returned to the cylinder 11 through an inlet tube 23 after it has passed through and/ or around the motor 14.

Disturbing noises would otherwise emanate from the motor-compressor unit' were it not for the ability of the muffler 16 to minimize the pulsations of the compressed gas. One way of muilling the sound of pulsating discharge gas is to cause the gasto travel through a series of alternately diverging and converging passages. Such is the type of muffler described herein.

The muffler 16 includes a casing or shell 24, preferably a hollow cylinder having a side wall 25 formed about a longitudinal axis and sealed at its ends by cap members 26. Interiorly of the shell 24 there is an elongated wall or partition 27 which lies in a plane containing the axis of the shell and divides the shell into two compartments. 'I'he shell 24 is provided with an inlet 29 and an outlet 30, and the partition 27 is disposed between them. In accordance with this invention, communication between the two compartments is provided by an elongated passage formed by and between a pair of plates 32 which form the partition 27.

The tubular passage between the shell compartments is preferably long in order that, with a longer flow path, the frequency range of the sounds deadened by the mufiler will be extended to include still lower frequencies.

Accordingly, this invention provides for the partition 27 to be comprised of a pair of flat metal plates 32, wherein the plates are held juxtaposed with one broad surface of each in mutually facing relationship. At least one of the plates 32, and preferably both of them, are embossed to provide elongated depressions 34 in their respective facing surfaces. Where both plates 32 are embossed, as in the illustrated embodiment, their depressions or recesses 34 are similarly formed so that they will complement each other and together define the elongated tubular passage between the plates.

To complete the flow path through the muffier 16 each plate 32 is further provided with an opening 36, at one end of the depression 34, which provides communication between the respective compartment and the passage between the plates. These openings 36 are offset from each other in the assembled partition 27.

In the interest of minimizing the number of dissimilar component parts in the assembly it is preferred that twin plates 32 be employed. Where, as illustrated, the shell 24 is cylindrical, each plate 32 is of at rectangular shape and has a similarly embossed depression in its complementary surface which extends along a non-rectilinear, preferably U-shaped line that is symmetrical with respect to the coincident axes or centerlines of the shell 24 and the partition 27. The depression 34 extends, therefore, from the plate opening 36 on one side of the axis or plate centerline to a blind terminus on the other side of the axis. Consequently, when the plates 32 are turned with respect to each other, and like sides of the plates are held together, their depressions 34 are in complementary relationship, their openings 36 are offset from each other and the plate centerlines, and an open ended, elongated passage is provided between the plates. The flow path through the mufer 16 can be traced from the shell inlet 29 into a iirst compartment, through the U- shaped passage in the partition 27, into the second compartment, and out the shell outlet 30.

The two plates 32 are preferably held together by brazing, welding or otherwise fastening together their facing surfaces. This plate-joining operation can be performed prior to inserting the plates into the shell 24; or, if furnace brazing is employed, the plates can be assembled in the shell with brazing material 33 therebetween and secured together at the same time that the end caps 26 and the edges of the partition 27 are joined to the shell. The latter method is preferred.

From the foregoing it will be apparent that a mutller having fewer dissimilar parts and the ability to munie sounds of lower frequency than mufers of comparable size and cost has been provided.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modications without departing from the spirit thereof.

What is claimed is:

1. A muier for a gas compreessor,

said mufer comprising a cylindrical shell and a wall containing the axis of said shell for partitioning the interior of said shell into iirst and second compartments,

said shell being provided with an inlet for said trst compartment and an outlet for said second compartment,

said wall comprising twin plates of flat rectangular shape,

each of said plates being provided with a depression in one surface thereof which extends from one side of said axis to the other along a U-shaped line that is symmetrical with respect to said axis,

each of said plates having an opening formed therein at one end of said line,

said plates being secured together with their respective depressions in complementary relationship and their respective openings` offset from each other so that a passage connecting said compartments is provided. Y

2. A mufer for a gas compressor comprising an elongated shell I and an elongated wall lying in a plane parallel to the major axis of said shell and partitioning the interior of the shell into tirst and second elongated compartments,

said shell being provided with an inlet for the rst compartment and an outlet for the second compartment,

said wall comprising a pair of plates held together with one broad surface of one plate in mutually facing relationship with one broad surface of the other plate,

one plate being provided with a depression in its mutually facing surface extending along an elongated U-shaped line and, together with the other plate, forming an elongated U-shaped passage, the legs of said U lying at opposite sides of,v and parallel to, the longitudinal axis of said wall,

one plate having an opening at one end of the passage to provide communication with one compartment and the other plate having an opening at the other end of the passage to provide communication with the other compartment,

whereby the pulsating gas flowing from said rst compartment to said second compartment is caused to flow through said elongated U-shaped passage to munie the pulsating sound of the gas.

References Cited in the tile of this patent UNITED STATES PATENTS 1,490,957 Birger Apr. 22, 1924 1,682,316 Williams Aug. 28, 1928 2,659,450 Baird Nov. 17, 1953 2,966,955 Smith et al. Jan. 3, 1961 FOREIGN PATENTS 65,450 Sweden June 26, 1928 719,975 Great Britain Dec. 8, 1954 1,123,100 France June 4, 1956 

1. A MUFFLER FOR A GAS COMPRESSOR, SAID MUFFLER COMPRISING A CYLINDRICAL SHELL AND A WALL CONTAINING THE AXIS OF SAID SHELL FOR PARTITIONING THE INTERIOR OF SAID SHELL INTO FIRST AND SECOND COMPARTMENTS, SAID SHELL BEING PROVIDED WITH AN INLET FOR SAID FIRST COMPARTMENT AND AN OUTLET FOR SAID SECOND COMPARTMENT, SAID WALL COMPRISING TWIN PLATES OF FLAT RECTANGULAR SHAPE, EACH OF SAID PLATES BEING PROVIDED WITH A DEPRESSION IN ONE SURFACE THEREOF WHICH EXTENDS FROM ONE SIDE OF SAID AXIS TO THE OTHER ALONG A U-SHAPED LINE THAT IS SYMMETRICAL WITH RESPECT TO SAID AXIS, EACH OF SAID PLATES HAVING AN OPENING FORMED THEREIN AT ONE END OF SAID LINE, SAID PLATES BEING SECURED TOGETHER WITH THEIR RESPECTIVE DEPRESSIONS IN COMPLEMENTARY RELATIONSHIP AND THEIR RESPECTIVE OPENINGS OFFSET FROM EACH OTHER SO THAT A PASSAGE CONNECTING SAID COMPARTMENTS IS PROVIDED. 